The supply run should keep the space station humming for years to come, and the shuttle astronauts in space through Thanksgiving.

Atlantis shot into a partly cloudy afternoon sky, to the delight of about 100 Twittering space enthusiasts who won front-row seats. It was NASA's first launch "tweetup," and the invitees splashed news - mostly tweeting "wow" about the liftoff - over countless cell phones and computers.

"We wish you good luck, Godspeed, and we'll see you back here just after Thanksgiving," launch director Mike Leinbach told shuttle commander Charles Hobaugh right before liftoff.

Atlantis will reach the space station Wednesday. As the shuttle blasted off, the station was soaring 220 miles above the South Pacific.

"We're excited to take this incredible vehicle for a ride and meet up with another incredible vehicle," Hobaugh said.

NASA wants to stockpile as many pumps, tanks, gyroscopes and other oversize equipment as possible at the space station, before the three remaining shuttles retire next fall. None of the other visiting spacecraft is big enough to carry such large pieces.

The space agency expects to keep the space station flying until 2015, possibly 2020 if President Barack Obama gives the go-ahead.

During their 11-day flight, Hobaugh and his crew - including the first orthopedic surgeon in space, Dr. Robert Satcher Jr. - will unload the nearly 30,000 pounds of equipment and experiments. Most of the gear will be attached to the outside of the space station on storage platforms.

Three spacewalks will be conducted beginning Thursday to hook everything up and get a jump on the next shuttle flight.

NASA officials were pleased with the punctual launch, but the Twittering invitees were downright ecstatic. They were among the first to sign up online last month for the opportunity to see a launch up close, and filed Twitter updates practically nonstop.

"Never been more proud to be a geeky, dorky, intelligent space fangirl!!" one wrote a few hours before liftoff.

"100 nerds against the road waving at the astrovan," another tweeted as the astronauts headed to the launch pad in late morning.

NASA estimates the 100 tweeters, or tweeps as they're called, have a following of more than 150,000. The space agency sees it as a beneficial outreach program, especially as the shuttle program winds down and the future remains murky. Obama has yet to chart a course for American astronauts, beyond the shuttle and station. A moon rocket under development is supposed to replace the shuttle, but the lunar exploration program is in jeopardy.

This is NASA's last shuttle flight of the year and one of only six remaining. If all goes as planned, the six spacemen will return to Earth the day after Thanksgiving, bringing home a seventh astronaut, Nicole Stott, who has been living at the space station since the end of August.

The astronauts will have to forgo the usual Thanksgiving fare. NASA did not pack any special turkey-and-trimming dinners aboard Atlantis. Hobaugh, the commander, didn't want any.

If the astronauts want poultry on Thanksgiving, they'll have to settle for turkey tetrazzini in rehydratable pouches or thermostabilized chicken fajitas. There's also plenty of barbecued beef brisket.